In recent years, with an improvement of a technique of semiconductors, semiconductor light emitting devices that output white light to be equipped in lighting apparatuses have become widely used.
Especially, semiconductor light emitting devices are compact and require low electric power. Therefore, semiconductor light emitting devices are suitable for installing in portable devices such as cellular-phones and cameras, and should explosively prevail in the near future.
A semiconductor light emitting device comprises: a semiconductor light emitting element that emits blue light; and translucent resin scatteredly including luminescent substance that converts blue light into greenish yellow light, greenish yellow being a complementary color of blue. The semiconductor light emitting device outputs light that looks white by outputting (a) a part of blue light that is emitted by a semiconductor light emitting element and transmits translucent resin without being converted by the luminescent substance, and (b) greenish yellow light that is generated as a result of conversion by the luminescent substance, at the same time in a proper proportion.
The details about the aforementioned semiconductor light emitting device are disclosed in Japanese Patent Publication No. 3257455 and No. 3399440 filled by the applicants of the present invention.
The aforementioned semiconductor light emitting device comprises a submount substrate and a flip chip semiconductor light emitting element that is mounted on the submount substrate, and needs a space for wire bonding on the submount substrate. Therefore, the submount substrate needs to be larger than the semiconductor light emitting element, and the semiconductor light emitting element is mounted on the submount substrate in an unbalanced position where a center of the semiconductor light emitting element does not coincide with a center of the submount substrate. It should be noted here that generally a main surface of the semiconductor light emitting element is substantially square and a main surface of the submount substrate is substantially rectangular.
Also, it is preferable that the semiconductor light emitting device is equipped with a cup-like reflection member to reflect the light emitted in parallel with a main light emitting surface by the semiconductor light emitting element so that the light travels in a direction perpendicular to a main light emitting surface.
The reflection member is a metal plate that has a conical-trapezoidal-shaped hole, as one example. On a bottom of the reflection member, the semiconductor light emitting element is provided. Radius of the reflection member decreases from a top toward a bottom.
Also a lens made of transparent resin or the like is provided over the reflection member to improve light distribution characteristic, and it is preferable to keep a radius on a bottom as small as possible taking the amount of materials and light focusing efficiency into account.
However, taking a light distribution characteristic into consideration, if a center of main light emitting surface of the semiconductor light emitting element is adjusted to coincide with a center of the reflection member, a space for wire bonding sticks out from the main light emitting surface. This would make a radius on a bottom of the reflection member considerably larger than a shape of the submount substrate. Nonetheless, adjusting a center of the submount substrate to coincide with a center of the reflection member should be avoided because it causes a degradation of light distribution characteristic. Also, reducing a space for wire bonding should be avoided because it increases bonding defects, lowers a yield ratio, and diminishes productivity due to an effort to improve accuracy.
The aim of the present invention is to provide a semiconductor light emitting device that can be set in a smaller space than the conventional ones without sacrificing light distribution characteristic and productivity and to provide a method for manufacturing the semiconductor light emitting device.